The X-ray diagnosis apparatus irradiates X-rays from an X-ray tube onto a patient, captures the X-rays transmitted through the subject using an X-ray detector, and the like, and generates a fluoroscopic image or a captured image, which is a shadowgram proportionate to the transit dose thereof. Subsequently, operators, including doctors, laboratory personnel, and the like (hereinafter, simply referred to as “operator”) observe the fluoroscopic image or captured image generated by the X-ray diagnosis apparatus, thereby diagnosing the subject.
Managing the dose irradiated onto the subject becomes very important upon diagnosis using the X-ray diagnosis apparatus above. This is because when the entrance dose is high, there is a danger of irradiation damage being caused to the body tissue.
Meanwhile, there is a case such that the intensity distribution of the X-rays being irradiated from the X-ray tube varies depending on the configuration of the X-ray diagnosis apparatus and conditions upon photographing. For example, there is a case such that when electron beams collide with an anode within the X-ray tube and X-rays are generated, the intensity distribution of the generated X-rays becomes varied due to a heel effect. Moreover, there is a case such that, depending on the collimator and conditions of the filter, the intensity of the X-ray transmitting a part of the irradiation field decreases. Furthermore, when a top is interposed between the X-ray tube and the subject, some X-rays are absorbed by the top at a part where the top is interposed, causing the intensity of the X-rays of the part to decrease.